Method and apparatus for splicing webs of cigarette paper or the like

ABSTRACT

The leading end of a fresh web which is stored on a reel is automatically spliced to an expiring web when the machine which consumes the expiring web and draws such expiring web from a source of supply is arrested in response to a signal from a detector which scans the supply of expiring web and produces the signal when the supply of expiring web is depleted to a predetermined minimum value. The consuming machine is started with a predetermined delay following completion of the splicing operation and is accelerated to normal operating speed in several stages at such a rate that the united webs which are accelerated in response to acceleration of the consuming machine are not subjected to excessive tensile stresses.

United States Patent [72] Inventor Gad-Joachim Wendt 2,991,827 7/1961 Hendrich et al. 242/584 X Hamburg-Bergedori, Germany 3,030,043 4/1962 Pinkham 242/583 [2]] Appl. No. 755,255 3,067,754 12/1962 Pinkham et a1. 131/21 [22] Filed Aug. 26, 1968 3,089,661 5/1963 Phillips, Jr. et al 242/584 [45] Patented June 22,1971 3,138,341 6/1964 Stone 242/58.4 [73] Assignee Hauni-Wcrlte Korber & Co. KG 3,165,276 l/1965 Stone et al. 242/583 llflm g- 'g t Germany 3,279,717 10/1966 Schubert 242/584 3; Priority (A;ug. 31, 1967 FOREIGN PATENTS [3 ermany [3 I] "63760 269,367 2/1914 Germany 131/21 Primary Examiner-Joseph S. Reich Attorney-Michael S. Striker [54] METHOD AND APPARATUS FOR SPLICING WEBS I F CIGARETTE PAPER OR THE LIKE 8 l D in F1 C g gs ABSTRACT: The leading end of a fresh web which is stored US- Cl. on a ee] is automatically spliced to an expiring web when the 2 machine which consumes the expiring web and draws such ex- [5 i ll'llweb from a source of supply is arrested in response to a [50] Field 01 Search 131/21, 66; i l fr m a detector hi h scans the supply of expiring web 242/583, and produces the signal when the supply of expiring web is depleted to a predetermined minimum value. The consuming [56] References CM machine is started with a predetermined delay following UNITED STATES PATIJENTS completion of the splicing operation and is accelerated to nor- 1,544,557 7/1925 Coldwell 242/583 mal operating speed in several stages at such a rate that the 1,924,583 8/1933 Wood 242/583 united webs which are accelerated in response to acceleration 2,613,042 10/1952 Dice, Jr. 242/58.4 of the consuming machine are not subjected to excessive ten- 2,957,637 10/1960 Hosken 242/584 sile stresses.

27 r I Cl 27a 2 22 1822 A RC 9 17:2 to 9am. f '3 O 1 7 8b 21 25b [.9a 1:: 2661 l i 22 13/ 15 i: L35 4 37 2 47 39 x METHOD AND APPARATUS FOR SPLICING WEBS F CIGARETTE PAPER OR THE LIKE BACKGROUND OF THE INVENTION The present invention relates to web splicing apparatus, particularly to apparatus which are adapted to form a splice between a fresh web of convoluted cigarette paper or mouthpiece paper and an expiring web which is being drawn into the rod forming mechanism of a continuous rod cigarette machine or into the wrapping station of a filter machine or filter cigarette machine. The invention also relates to a method of uniting an expiring web with the leading end of a fresh web.

Splices between an expiring web and the leading end of a fresh web can be formed while the expiring web is running or while the expiring web is at a standstill. The splicing operation is more complicated when the expiring web is running because the leading end of the fresh web must be accelerated to the speed of the expiring web and the splice must be formed between a travelling portion of the expiring web and a travelling portion of the fresh web. Such splices are often unreliable and the number of parts necessary to insure fully automatic acceleration of the fresh web, fully automatic splicing of the two webs, and automatic severing of the remainder of the expiring web is excessive. In accordance with presently prevailing practice, a splice between a stationary part of the expiring web and a stationary fresh web is formed by accumulating a supply of expiring web in a reservoir located downstream of the splicing station, arresting the trailing end of the thus accumulated supply while the consuming machine which receives the web continues to draw web material from the reservoir,'and forming a splice between the arrested trailing end of the stored expiring web and the leading end of the fresh web. Such splicing, too, is quite complicated and involves the use of expensive apparatus, particularly because the leading end of the spliced fresh web must be suddenly accelerated to full operating speed of the consuming machine when the supply of expiring web in the reservoir is exhausted. This often leads to breakage of the web and causes considera ble losses in output of the consuming machine. Furthermore, the reservoir occupies a substantial amount of space and the apparatus must be provided with two drives.

SUMMARY OF THE INVENTION One of the objects of my present invention is to provide a novel and improved method of uniting the leading end of a stationary fresh web with an expiring web which is being fed to a consuming station in a consuming machine, particularly in a continuous rod cigarette machine, in such a way that the splice between the two webs can be formed while the webs are stationary but without materially affecting the output of the consuming machine and/or the quality of products which are being produced or treated at the consuming station.

A further object of the invention is to provide an apparatus for uniting a stationary fresh web with an arrested expiring web in such a way that the formation of the splice is completed within a short interval of time and that the completion of such splice automatically triggers a series of operations which lead to acceleration of the fresh web to the full operating speed of the consuming machine.

An additional object of the invention is to provide an apparatus of the just outlined character wherein the splicing operation is triggered automatically when the supply of expiring web is depleted, and wherein the remainder of the expiring web is automatically severed from the splice and is moved out of the way in response to completion ofthe splicing operation.

A concomitant object of the invention is to provide a relatively inexpensive, compact, and reliable web splicing up paratus which can complete the splice rapidly and with a minimal delay following substantial depletion of the expiring web, and which allows for proper placing of the fresh web into requisite position for splicing of its leading end prior to exhaustion ofthe expiring web.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved web splicing apparatus itself, however, both as to its constructionand its mode of operation, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of a specific embodiment with reference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic side elevational view of a splicing apparatus which embodies the invention;

FIG. 2 is a view similar to FIG. 1 illustrating the splicer of the apparatus in operative position;

FIG. 3 is a view similar to FIG. 1 illustrating the splicer in a position it assumes upon completion of the splicing operation; and

FIG. 4 is a schematic diagram of the electric circuit of the splicing apparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENT The splicing apparatus which is illustrated in FIG. 1 comprises a main support 1 for a source of supply 3, here shown as a reel which pays out the expiring web 8, for example, a web of cigarette paper which is being fed to the wrapping mechanism of a continuous cigarette rod making machine. The reel 3 is mounted on a shaft 2. The support 1 also carries a second shaft 4 for a reel 6 which contains a supply of convoluted fresh web 13. The expiring web 8 travels through a braking device 90, through an automatic splicer 11, and between the advancing rolls 46, 47 of a drive 12. The cigarette rod making machine which embraces the drive 12 is shown schematically at RCM. A cigarette rod, with a web of cigarette paper convoluted around a tobacco filler rod, is shown at R.

The fresh web 13 is threaded through a second braking device 9b, thereupon through the aforementioned splicer 11 and has a leading end 16 provided with a layer 15 of adhesive which can bond the web 13 to the web 8. The layer 15 of adhesive can be applied to one side of a uniting band whose other side is also coated with adhesive and adheres to the leading end 16. Such a band would be placed manually in the position shown in FIG. 1.

The braking device 9a comprises rollers 17a, 18a and the expiring web 8 is trained over these rollers in a manner as shown in FIG. 1. The rollers 17a, 18] are rotatable on a webremoving lever 19a which is pivotable on a pin 21a and serves the additional purpose of removing the remainder 8a of the expiring web 8 from the splicing station subsequent to severing of such remainder from the main part of the web 8. A gear 220 which is secured to the removing lever 19a coaxially with the pivot pin 21a meshes with a second gear 23a. The

latter is biased by a spring 240 which tends to rotate it in a counterclockwise direction (arrow 260). This gear 230 is further connected with one end of a brake band 2711 which is trained over a friction disc 28a on the shaft 2. The other end of the brake band 27a is fixedly anchored in a stationary part of the frame. The parts 17a to 24a together constitute an actuating unit which initiates the operation of the brake band 27a.

The second braking device 912 is identical or substantially identical with the braking device 9a. It comprises rollers 17b, 18b, a removing lever 19b, a pivot pin 21b, gears 22b, 23b, a spring 24b which biases the gear 23b in the direction indicated by arrow 26b, and a brake band 27b. The latter is trained over a friction disc 28b mounted on the shaft 4. One end of the band 27b is secured to a stationary frame member.

The automatic splicer 11 includes an electromagnet 31 having terminals 30 and comprising a reciprocable armature 32 carrying a movable splicing member or ram 33. A stationary splicing member or anvil 34 has a splicing surface which is adjacent to the expiring web 8 and is provided with suction ports 36 in communication with a suction chamber 37 provided in the interior of the anvil 34. The suction chamber 37 accommodates a vacuum switch 39 having a movable contact 38 which engages stationary contacts and closes the vacuum switch when the ports 36 are sealed by the leading end 16 of the fresh web 13. The armature 32 of the electromagnet 31 is further connected with a movable cutter or knife 42 which includes a blade 41.

The drive 12 for the expiring web 8 comprises the aforementioned advancing rollers 46, 47 the former of which is rotated by the motor 48 ofthe machine RCM. The motor 48 is a reversible-polarity polyphase induction motor and can be operated at two speeds. The conductors which supply current to that winding which causes the motor 48 to operate at a higher (normal) speed are shown at 49. The conductors 51 supply current to that winding which causes the motor 48 to operate at a lower speed. The numeral 52 denotes a guide roll which is installed upstream ofthe splicer 11.

The splicing apparatus further comprises a detector which serves to scan the quantity of expiring web 8 on the reel 3. This detector comprises a photoelectric receiver 53 and a light source (not shown). The receiver 53 produces a signal when the diameter of the reel 3 is reduced to a predetermined minimum value.

FIG. 4 illustrates the electric circuit of the web splicing apparatus. The photoelectric receiver 53 of the detector is connected with anamplifier 61 whose output is connected with the winding 62 of a relay 63 including a second winding 64 and relay contacts 66, 67, 68, 69, 71. The contacts 6669 and 71 assume the broken-line closed positions only when the winding 62 is energized simultaneously with the winding 64. The latter winding is connected in a circuit which is controlled by the movable contact 38 of the vacuum switch 39. This cir cuit further includes an energy source 72. Due to the fact that the vacuum switch 39 is in circuit with the winding 64 of the relay 63, the anvil 34 can perform the additional function of detecting whether or not the leading end 16 of the fresh web 13 is in requisite position for splicing to the expiring web 8, i.e., the anvil can prevent splicing if the leading end 16 does not seal the ports 36.

The contact 66 of the relay 63 is a holding contact and the contact 67 controls the winding 73 ofa disconnecting relay 74 for the motor 48. This second relay contact 67 is in series with a second energy source 76. The disconnecting relay 74 has a second winding 77 which is energized as long as the master switch 78 of the machine RCM remains closed. The design of the relay 74 is such that its contact 79 opens when the winding 73 is energized simultaneously with the winding 77. The contact 79 controls a motor relay 81 which can establish or terminate a connection between the conductors 49 of the motor 48 and a source 83 of polyphase current. The contacts 82 of the relay 81 are closed when the winding 77 of the relay 74 is energized and when the winding 73 is deenergized.

The contact 68 of the relay 63 is in circuit with a time-lag device 84 and with the winding of a relay 86 which closes its contact 87 for a short interval of time in response to energization of its winding and automatically opens the contact 87 irrespective of the condition of such winding. The contact 87 can connect one terminal 30 of the electromagnet 31 with an energy source 88. Relays which can perform the function of the relay 86 are produced, for example, by Schiele Industriewerke K. G., 7746 Hornberg, Germany and are known as EW" relays. The parts 84, 86 and 31 control the operation of the splicer 11.

The contact 69 of the relay 63 is in circuit with a (second) time-lag device 89 and with the winding of a further motor relay 91 having contacts 92 which can connect the conductors 51 of the motor 48 with the source 83. The contact 71 of the relay 63 is in circuit with a third time-lag device 93 and with the winding of a relay 94 having a contact 96 which is in the holding circuit of the relay 63 and can complete the circuit of the winding 64 when the winding of the relay 94 is energized. The energy source 72 is in series with the winding 64 and contact 96. A further energy source 97 is in circuit with the timelag devices 84, 89, 93. The delays furnished by the devices 84, 89, 93 are selected in such a way that the delay furnished by the device 89 exceeds that furnished by the device 84 but is less than that furnished by the device 93. Each of these timelag devices may comprise a conventional R-C unit and they may form part of the relays 86, 94 or of the motor relay 9]. As can be seen in FIG. 4, the devices 84, 93 respectively delay energization of the relays 86, 94 and the device 89 delays energization of the relay 91.

The relays 91, 94 together constitute a starter for accelerating the motor 48 and hence the drive 12 from zero speed to normal operating speed in automatic response to completion of the splicing operation. The time-lag device 84 initiates automatic operation of the splicer 11 with a predetermined delay following inactivation of the drive 12 by relays 63, 74, 81. The time-lag device 89 initiates the operation of the aforementioned starter with a predetermined delay following operation of the splicer l1 and the time-lag device 93 initiates the second stage of acceleration of the motor 48 and drive 12 with a predetermined delay following completed acceleration to the first speed.

The operation is as follows:

Prior to splicing, a reel 6 containing a full supply of fresh web 13 is mounted on the support 1 in the position shown in FIG. 1. The fresh web 13 is then trained over the rollers 18b, 17b of the braking device 9b and its leading end 16 is placed onto the top surface of the anvil 34. As stated before, the leading end 16 carries a layer 15 of adhesive which is preferably applied to one side of a customary uniting band whose other side is also coated with adhesive and is adjacent to the underside of the travelling expiring web 8. The leading end 16 of the fresh web 13 then seals the ducts 36 in the anvil 34. Thus, suction builds up in the chamber 37 to attract the leading end 16 to the top surface of the anvil 34, and such suction also causes closing of the vacuum switch 39. However, the relay 63 remains inactive because its winding 62 is deenergized until the supply of expiring web 8, i.e., the diameter of the reel 3, is reduced to a predetermined minimum value at which the photoelectric receiver 53 responds. The fresh reel 6 is now ready and its web 13 can be spliced to the web 8 in response to a signal from the amplifier 61. This is shown in FIGS. 1 and 4.

The expiring web 8 travels around the rollers 18a, 17a of the braking device 90, around the guide roll 52, below the blade 41 of the cutter 42 and along the underside of the ram 33 which is spaced from the top surface of the anvil 34. This expiring web is drawn by the advancing rolls 46, 47 and is fed into the wrapping mechanism of the machine RCM. The expiring web 8 is a taut to maintain the lever 19a in the position shown in FIG. 1 in which the lever 19a is turned in a counterclockwise direction and causes the spring 24a to store energy. The brake band 27a is loose, i.e., it has a certain amount of slack so that it does not oppose rotation of the friction disc 28a with the shaft 2. lfthe expiring web 8 breaks, the spring 24 is free to contract and rotates the gear 23a in a counterclockwise direction indicated by arrow 26a whereby the band 27a tightens around the peripheral surface of the disc 28a to brake the shaft 2 and the expiring reel 3. Thus, the reel 3 is arrested in automatic response to breakage of the expiring web 8.

The master switch 78 of the machine RCM is closed so that the winding 77 of the relay 74 is energized. Thus, the relay contact 79 is closed and the relay 81 is energized so that the motor 48 drives the advancing roller 46 at the normal (higher) operating speed. In other words, the conductors 49 are connected with the energy source 83 by way of contacts 82 which then assume the solid-line positions shown in FIG. 4.

When the diameter of the reel 3 decreases to a predetermined value, the receiver 53 produces a signal which causes the amplifier 61 to energize the winding 62 of the relay 63. The winding 64 is already energized because the vacuum switch 39 is closed due to scaling of ducts 36 by the leading end 16 of the fresh web 13. Thus, the relay 63 moves its contacts 66-69 and 71 to the broken-line positions shown in FIG. 4 whereby the contact 66 completes the holding circuit and the contact 67 energizes the winding 73 of the relay 74 whereby the relay 74 opens its contact 79 (broken-linc position of FIG. 4) to deenergize the relay 81. The contacts 82 move to the broken-line (open) positions and disconnect the conductors 49 from the energy source 83. Consequently, the drive of the machine RCM is arrested and the moving parts of this machine are allowed to come gradually to a full stop.

The delay furnished by the time-lag device 84 is long enough to insure that the machine RCM is at a standstill when the electromagnet 31 is energized. This device 84 then causes energization of the relay 86 which closes the contact 87 and thus completes the circuit of the electromagnet 31. The latter moves its armature 32 downwardly whereby the ram 33 causes the expiring web 8 to move against the adhesive-coated upper side of the aforementioned uniting band on the leading end 16 of the fresh web 13, i.e., the web 8 is spliced to the web 13. It will be seen that the splicing operation is carried out while the webs 8 and 13 are idle, Energization of the electromagnet 31 is of short duration (due to the aforedescribed nature of the relay 86) so that the ram 33 immediately returns from the extended position shown in FIG. 2 back to the retracted position shown in FIG. 1. During movement of the armature 32 toward the position shown in FIG. 2, the blade 41 of the cutter 42 automatically severs the expiring web 8 upstream of the splicing station. As shown in FIG. 1, the spring 24a causes the lever 19a to turn in a clockwise direction in response to severing of the expiring web 8 whereby the remainder 8a of this web is automatically moved away from the splicing station. The spring 24a also causes the brake band 27a to hold the shaft 2 and reel 3 against rotation by way of the friction disc 280.

When the splicing and severing steps are completed, the ram 33 returns to the position of FIG. 1 in response to the action of a suitable spring (not shown) which tends to maintain the armature 32 in retracted position. Energization of the electromagnet 31 is of short duration because the splicing and severing steps take up a relatively short interval of time. Thus, the seam between the overlapping edges of the tube formed in the wrapping mechanism around the tobacco rod does not open up during the interval when the machine is idle. The delay determined by the time-lag device 89 expires in the meantime so that the relay 91 becomes energized and its contacts 92 move to the broken-line positions of FIG. 4 to connect the conductors 51 with the energy source 83 and to thus start the motor 48 of the machine RCM at the lower speed. The rate of acceleration of the motor 48 to such lower speed is selected with a view to avoid tearing of the web 13. The splice between the trailing end 812 of the expired web and the leading end 16 of the web 13 then advances beyond the splicing station as shown in FIG. 3. The webs 8 and 13 are taut and advance at the slower speed.

Upon elapse of a further delay which is determined by the time-lag device 93 and which is selected with a view to insure that the motor 48 is accelerated to the lesser or lower speed as well as to insure that the splice between the webs 8, 13 has already reached the wrapping mechanism of the machine RCM and forms part of a tube which is provided around the travelling tobacco rod, the relay 94 is energized and causes its contact 96 to open the holding circuit for the relay 63. Such position of the contact 96 is shown in FIG. 4 by broken lines. The contacts 6669 and 71 of the relay 63 return to the solidline positions of FIG. 4 and the relay 63 thereupon remains deenergized despite renewed closing of the contact 96 because the web 13 is taut and moves away from the top surface of the anvil 34 so that the suction chamber 37 is connected with the atmosphere by way of the ducts 36. In other words, the vacuum switch 39 opens and causes dcencrgization of the winding 64 in the relay 63. Consequently, the relay 91 is disconnected from the energy source 97.

The relay 63 also causes tlccuergixation of the relay inding 73 whereby the relay 74 closes the switch 79 (because the winding 77 is energized due to the fact that the master switch 78 is closed). The switch 79 energizes the relay 81 which closes the contacts 82 and thus connects the conductors 49 with the energy source 83. The motor 48 is then accelerated to its higher operating speed and the advancing rollers 46, 47 accelerate the fresh web 13 (which is now the expiring web). This completes the splicing operation.

The shaft 2 with the expired reel 3 and with the braking device is then removed from the support 1 and the expiring reel 6 (with the braking device 9b) is moved in the direction of arrow 7 (FIG. 1) to take the place of the removed reel 3. A fresh reel is mounted on the shaft 2 and this shaft is thereupon mounted in the support 1 to take the place of the shaft 4. The web of the fresh reel is threaded around the rollers 17a, 18a and its leading end is placed onto the top surface of the anvil 34 so that it seals the ports 36 and causes closing of the vacuum switch 39. However, and as described hereinabove, closing of the vacuum switch 39 cannot initiate a fresh splicing operation until and unless the receiver 53 produces a signal which indicates that the supply of expiring web 13 is reduced to a predetermined minimum. Thus, and since the reel 6 is shifted to the right, as viewed in FIG. 1, before the leading end of the fresh reel is placed onto the anvil 34, no premature splicing action can take place prior to a predetermined reduction in the diameter of the reel 6 in the new position on the support 1.

It is clear that the splicer 11 can be designed to roll a pressure splice instead of providing an adhesive bond between the expiring and fresh webs or that the splicer can establish an adhesive bond in addition to providing a pressure splice. In such instances, the top surface of the anvil 34 and/or the underside of the ram 33 is provided with teeth, needles or analogous protuberances which can cause the formation of a pressure splice similar to that provided by apparatus disclosed in the U.S. Pat. No. 3,089,661 to Phillips,.lr., et al.

A very important advantage of the improved apparatus is that the splicing of an expiring web to a fresh web consumes very little time so that, even though the webs are spliced to each other while they are at a standstill, the seam between the overlapping edges of the tube formed by the web around the tobacco rod in the wrapping mechanism is not destroyed even though the drive of the machine is temporarily disconnected. Splicing of webs which are at a standstill is desirable because it is much safer than splicing of travelling webs. Furthermore, the splicing operation is initiated and carried out in a fully automatic way so that the persons in charge need not supervise the expiring reel, as long as a fresh reel is properly mounted on the support 1 and the leading end of its web overlies the anvil 34. Temporary stoppage of the machine RCM for a short period of time which is required to complete the splicing operation has very little effect on the output and/or quality of cigarettes. The apparatus of the present invention can operate properly without resorting to a magazine for an expiring reel which is necessary in presently known web splicing apparatus wherein the splice is formed between two stationary webs. The expenses involved in connection with the provision of aforediscussed controls for the motor of the consuming machine are considerably less than those involved in insuring that the magazine of a conventional web splicing apparatus invariably contains a requisite amount of reserve material so that the splice can be rolled or otherwise formed between a stationary portion of the expiring web and a stationary portion of the fresh web.

What I claim as new and desire to be protected by Letters Patent is set forth in the appended claims.

1. A method of uniting the leading end of a fresh web with an expiring web which is being drawn from a source of supply by a cigarette rod making machine wherein the web is convoluted around a traveling tobacco rod when the rod cigarette machine is in operation, comprising the steps of scanning the supply of expiring web; interrupting the operation of the rod cigarette machine in response to depletion of said supply of expiring web to a predetermined minimum value; mechanically splicing the expiring web to the leading end of the fresh web while the rod cigarette machine is idle; and accelerating the cigarette rod making machine at a rate which is below that at which the thus accelerated united webs would tend to break, said accelerating step comprising accelerating the cigarette rod making machine to a lower first speed and thereupon accelerating the cigarette rod making machine to a higher second speed, the acceleration to said second speed being initiated with such a delay that the splice between the expiring and fresh webs at least reaches the tobacco rod while the machine is operated at said first speed.

2. A method of uniting the leading end of a fresh web with an expiring web which is being drawn from a source of supply by a tobacco processing machine which is normally operated at a predetermined speed, comprising the steps of scanning the supply of expiring web; reducing the speed of the tobacco processing machine and of the expiring web in response to depletion of said supply of expiring web to a predetermined minimum value; mechanically splicing the expiring web to the leading end of the fresh web upon completion of said speed reducing step; and accelerating the tobacco processing machine to said predetermined speed upon completion of said splicing step at a rate which is below that at which the thus accelerated united webs would tend to break.

3. A method as defined in claim 2, wherein said splicing step is carried out with a predetermined delay following said speed reducing step.

4. A method as defined in claim 2, wherein said accelerating step is initiated with a predetermined delay following completion of said splicing step.

5. A method as defined in claim 2, wherein said accelerating step is initiated with a predetermined delay following said speed reducing step.

6. A method as defined in claim 2, wherein said accelerating step includes accelerating the tobacco processing machine to a relatively lower first speed and thereupon accelerating the machine to said predetermined speed.

7. A method as defined in claim 6, wherein the acceleration to said predetermined speed is initiated with a predetermined delay following acceleration to said first speed.

8. A method as defined in claim 2, further comprising the step of placing the leading end of the fresh web into a predetermined position with reference to the path of the expiring wcb prior to start of said splicing step. 

1. A method of uniting the leading end of a fresh web with an expiring web which is being drawn from a source of supply by a cigarette rod making machine wherein the web is convoluted around a traveling tobacco rod when the rod cigarette machine is in operation, comprising the steps of scanning the supply of expiring web; interrupting the operation of the rod cigarette machine in response to depletion of said supply of expiring web to a predetermined minimum value; mechanically splicing the expiring web to the leading end of the fresh web while the rod cigarette machine is idle; and accelerating the cigarette rod making machine at a rate which is below that at which the thus accelerated united webs would tend to break, said accelerating step comprising accelerating the cigarette rod making machine to a lower first speed and thereupon accelerating the cigarette rod making machine to a higher second speed, the acceleration to said second speed being initiated with such a delay that the splice between the expiring and fresh webs at least reaches the tobacco rod while the machine is operated at said first speed.
 2. A method of uniting the leading end of a fresh web with an expiring web which is being drawn from a source of supply by a tobacco processing machine which is normally operatEd at a predetermined speed, comprising the steps of scanning the supply of expiring web; reducing the speed of the tobacco processing machine and of the expiring web in response to depletion of said supply of expiring web to a predetermined minimum value; mechanically splicing the expiring web to the leading end of the fresh web upon completion of said speed reducing step; and accelerating the tobacco processing machine to said predetermined speed upon completion of said splicing step at a rate which is below that at which the thus accelerated united webs would tend to break.
 3. A method as defined in claim 2, wherein said splicing step is carried out with a predetermined delay following said speed reducing step.
 4. A method as defined in claim 2, wherein said accelerating step is initiated with a predetermined delay following completion of said splicing step.
 5. A method as defined in claim 2, wherein said accelerating step is initiated with a predetermined delay following said speed reducing step.
 6. A method as defined in claim 2, wherein said accelerating step includes accelerating the tobacco processing machine to a relatively lower first speed and thereupon accelerating the machine to said predetermined speed.
 7. A method as defined in claim 6, wherein the acceleration to said predetermined speed is initiated with a predetermined delay following acceleration to said first speed.
 8. A method as defined in claim 2, further comprising the step of placing the leading end of the fresh web into a predetermined position with reference to the path of the expiring web prior to start of said splicing step. 